module Shifter(value_in, shiftop, shiftamt, result);

	// Entradas
	input signed [31:0]		value_in;
	input 		  [1:0]		shiftop;
	input 		  [4:0]		shiftamt;
	
	// Saída
	output signed [31:0]	result;
	
	...
	
endmodule

